This invention relates to new compositions comprising an oligopeptide, more specifically to such compositions that enable the transport or delivery of an oligopeptide through the skin or epithelium (also referred to as “transdermal delivery”), and that therefore may be used as topical applications for providing an oligopeptide to a subject, for various therapeutic, aesthetic and/or cosmetic purposes, as described herein.
Botulinum toxins (also known as botulin toxins or botulinum neurotoxins) are neurotoxins produced by the gram-positive bacteria Clostridium botulinum. They act to produce paralysis of muscles by preventing synoptic transmission or release of acetylcholine across the neuromuscular junction, and are thought to act in other ways as well. Their action essentially blocks signals that normally would cause muscle spasms or contractions, resulting in paralysis.
Allan B. Scott first used botulinum toxin A (BTX-A) in monkeys in 1973. Scott demonstrated reversible ocular muscle paralysis lasting 3 months (Lamanna, Science, 130:763-772 (1959)). Soon afterwards, BTX-A was reported to be a successful treatment in humans for strabismus, blepharospasm, and spasmodic torticollis (Baron et al. In: Baron E J, Peterson L R. Finegold S M (Eds), Bailey & Scotts Diagnostic Microbiology, St. Louis, Mo.: Mosby Year Book, 504-523 (1994); Carruthers and Carruthers, Adv Dermatol, 12:325-348 (1997); Markowitz, In: Strickland GT (Eds) Hunters Tropical Medicine, 7th ed. Philadelphia: W.B. Saunders. 441-444 (1991)). In 1986, Jean and Alastair Carruthers, a husband and wife team consisting of an ocuplastic surgeon and a dermatologist, began to evolve the cosmetic use of BTX-A for treatment of movement-associated wrinkles in the glabella area (Schantz and Scott, In Lewis GE (Ed) Biomedical Aspects of Botulinium. New York: Academic Press. 143-150 (1981)). The Carruthers' use of BTX-A for the treatment of wrinkles led to their seminal publication of this approach in 1992 (Schantz and Scott. In Lewis GE (Ed) Biomedical Aspects of Botulinum. New York: Academic Press. 143-150 (1992)). By 1994, the same team reported experiences with other movement-associated wrinkles on the face (Scott, Ophthalmol, 87:1044-1049 (1980)). This in turn led to the birth of the era of cosmetic BTX-A treatment.
Skin protects the body's organs from external environmental threats and acts as a thermostat to maintain body temperature. It consists of several different layers, each with specialized functions. The major layers include the epidermis, the dermis and the hypodermis. The epidermis is a stratifying layer of epithelial cells that overlies the dermis, which consists of connective tissue. Both the epidermis and the dermis are further supported by the hypodermis, an internal layer of adipose tissue.
The epidermis, the topmost layer of skin, is only 0.1 to 1.5 millimeters thick (Inlander, Skin, New York, N.Y.: People's Medical Society, 1-7 (1998)). It consists of keratinocytes and is divided into several layers based on their state of differentiation. The epidermis can be further classified into the stratum corneum and the viable epidermis, which consists of the granular melphigian and basal cells. The stratum corneum is hygroscopic and requires at least 10% moisture by weight to maintain its flexibility and softness. The hygroscopicity is attributable in part to the water-holding capacity of keratin. When the horny layer loses its softness and flexibility it becomes rough and brittle, resulting in dry skin.
The dermis, which lies just beneath the epidermis, is 1.5 to 4 millimeters thick. It is the thickest of the three layers of the skin. In addition, the dermis is also home to most of the skin's structures, including sweat and oil glands (which secrete substances through openings in the skin called pores, or comedos), hair follicles, nerve endings, and blood and lymph vessels (Inlander, Skin, New York, N.Y.: People's Medical Society, 1-7 (1998)). However, the main components of the dermis are collagen and elastin.
The hypodermis is the deepest layer of the skin. It acts both as an insulator for body heat conservation and as a shock absorber for organ protection (Inlander, Skin, New York, N.Y.: People's Medical Society, 1-7 (1998)). In addition, the hypodermis also stores fat for energy reserves. The pH of skin is normally between 5 and 6. This acidity is due to the presence of amphoteric amino acids, lactic acid, and fatty acids from the secretions of the sebaceous glands. The term “acid mantle” refers to the presence of the water-soluble substances on most regions of the skin. The buffering capacity of the skin is due in part to these secretions stored in the skin's horny layer.
One of the principal functions of skin is to provide a barrier to the transportation of water and substances potentially harmful to normal homeostasis. The body would rapidly dehydrate without a tough, semi-permeable skin. The skin helps to prevent the entry of harmful substances into the body. Although most substances cannot penetrate the barrier, a number of strategies have been developed to selectively increase the permeability of skin with variable success.
Botulinum toxin type A is said to be the most lethal natural biological agent known to man. At the same time, the muscle-paralyzing effects of botulinum toxin have been used for therapeutic effects. Controlled administration of botulinum toxin has been used to provide muscle paralysis to treat conditions, for example, neuromuscular disorders characterized by hyperactive skeletal muscles. Conditions that have been treated with botulinum toxin include hemifacial spasm, adult onset spasmodic torticollis, anal fissure, blepharospasm, cerebral palsy, cervical dystonia, migraine headaches, strabismus, temperomandibular joint disorder, and various types of muscle cramping and spasms. More recently the muscle-paralyzing effects of botulinum toxin have been taken advantage of in therapeutic and cosmetic facial applications such as treatment of wrinkles, frown lines, and other results of spasms or contractions of facial muscles.
In all treatments currently used, the botulinum toxin is administered by carefully controlled or monitored injection, creating large wells of toxin at the treatment site. A few scattered references to topical treatment are present in the literature. For example, assertions that botulinum toxin may be applied topically are made in U.S. Pat. No. 6,063,768 of Eric R. First, but no information is given as to how this may be accomplished. In another patent in which First is named as an inventor. U.S. Pat. No. 6,087,327 (of Pearce and First), mention is made that the botulinum toxin may be topically administered by solubilization in normal phosphate buffer containing gelatin stabilizer and administered topically into the nasal cavity of a dog. The patent cites a publication by Shaari et al. (Otolaryngol. Head Neck Surg. 2; 566, 1995) in which such an experiment was conducted. German published patent application 198 52 981 describes topical compositions containing botulinum toxin and dimethyl sulfoxide for treatment of hyperhidrosis. An example in which a single patient was treated is included.
U.S. Pat. No. 5,670,484 (Binder) describes the use of botulinum toxin in treating cutaneous cell-proliferative disorders (for example, psoriasis and dermatitis) using neurotoxins, including botulinum toxin. The patent asserts that compositions may be applied topically, but no examples of suitable formulations are given, and in the test examples the botulinum toxin was administered by injection. U.S. published application 2003/0113349 (Coleman III) represents that topical formulations containing botulinum toxin may be used to treat hyperactive glandular conditions in the skin. However, the description relates to conditions in cutaneous glands and does not discuss transdermal applications. In addition, like most of the publications discussed here, it contains no working examples. Finally, U.S. published application 2004/0009180 (Donovan) discloses the use of botulinum toxin in topical treatments for a number of conditions, some of which apparently involve transdermal delivery, for instance, topical application to relax muscles. The publication states that transdermal delivery is accomplished by use of an enhancing agent. Agents said to be suitable for this purpose include various alcohols, including polyalcohols, amines, amides, transferomes and liposomes. The examples are all written in the present tense, indicating that some or all may be conceptual rather than empirical.
One approach to solving the problems associated with botulinum toxin therapy is to use fragments of the toxin or other agents that interfere with the SNARE complex. The SNARE complex is an assembly of three proteins that plays a central role in neuronal exocytosis, the process where neurotransmitter loaded vesicles fuse with the neuron cell membrane and expel their contents. (Gutierrez, L. M., et. al. FEBS Lett. 372, 39-43 (1995); Gutierrez, L. M., et. al. J. Biol. Chem. 272, 2634-2639 (1997); Ferrer-Montiel, A. V., et. al. FEBS Lett. 435,84-88 (1998))
This work has resulted in identification of effective oligopeptides of 20 or more amino acids. However, these agents like botulinum toxins themselves were also found to have extremely poor ability to penetrate skin. More recently, a 6 amino acid peptide with the sequence glutamic acid-glutamic acid-methionine-glutamine-arginine-arginine (EEMQRR (SEQ ID NO: 1)) has been shown to retain some activity in one model. (C. Blanes-Mira, et. al. International Journal of Cosmetic Science, 2002, 24, 303-310).
This hexapeptide, when derivatized to improve skin penetration and employed at very high concentrations such as 10% affords wrinkle reduction in certain cases (acetyl hexapeptide or ARGIRELINE®). However, the transdermal penetration of this peptide even when derivatized with palmitate or acylated as in ARGIRELINE® remains so low that efficacy in wrinkle reduction requires high concentrations of expensive compounds-most of which does not cross the skin. Safety advantages relative to complete botulinum toxins are likely but have yet to be established in these applications given with the high load necessitated by low skin penetration. Hence, the limitations of botulinum toxins in terms of route of administration are largely preserved with these agents.